Apparatus for reading microdocuments

ABSTRACT

Apparatus enabling microdocuments to be read by projection on to a translucent screen, using a mirror to reflect the light beam; this, as well as the screen, folds into a case which serves as a base for the apparatus and contains dry cells to feed electricity to the light source. The essential characteristic of this folding &#39;&#39;&#39;&#39;reader&#39;&#39;&#39;&#39; is the use of a miniature bulb in combination with means of recovering the power radiated, making it possible to use dry cells in series with a lower voltage than usual, and at the same time projecting the part of the apparatus which are close to the light source, from excessive heat.

Cordonnier States P 1191 [5 APPARATUS FOR READING 3,413,061 11/1968 Simpson 6131. 353/52 MICRODOQUMENTS 1,256,522 2/1918 Croxton 353/99 1,457,646 6/1923 W1lson 240/4135 C [75] Inventor: Gerard Anatole Cordonnier, Ville v Ayligylfrancg FOREIGN PATENTS OR APPLICATIONS 7 54 F 1 1 AS99199 Le Materiel Compact, 333,23 251325 6222mm 333533 [22] Filed: Feb. 1, 1972 Primary Examiner-Harry N. Haroian [21] Appl 222623 Attorney, Agent, or FirmWilliam Anthony Drucker 30 Foreign Application Priority Data [57] ABSTRACT Dec. 31, 1971 France,..., 71.47791 Apparatus enabling microdocumems to be read y projection on to a translucent screen, using a mirror to 2% 8 353/77 33;;232; reflect the light beam; this, as well as the screen, folds B 103 into a case which serves as a base for the apparatus 1 He 0 9899 and contains dry cells to feed electricity to the light source. The essential characteristic of this folding 56 v R f Ct d reader" is the use ofa miniature bulb in combination 1 v e erences l e with means of recovering the power radiated, making UNITED STATES PATENTS it possible to use dry cells in series with a lower volt- 3,667,839 6/1972 Artaud 353/27 age than usual, and at the same time projecting the 3,479,116 11/1969 Anderson "353/77 part the apparatus are close to the 1,248,456 12/1917 Clark 353/99 Source, f excessive heat 3,318,184 5/1967 Jackson 353/99 1,394,896 10/1921 Halvorson 340/4135 R 2 Claims, 6 Drawing Figures l APPARATUS FOR READING MICRQDOCUMENTS This invention relates to an apparatus for reading microdocuments, particularly microfiches.

Various types of apparatus for reading microdocuments exist, some of them rigid, heavy and bulky, others simplified, folding and containable in small cases, and sometimes independent from the point of view of the electric feed to the light bulb. Inthe latter case, either rechargeable batteries with a charger incorporated in the apparatus, or dry cells, are used. The disadvantage of this kind of apparatus is that the dry cells or batteries are comparatively heavy, and'discharge quickly if a light source is used which is powerful enough to give a bright enough image on the screen of the reader. Moreover, a sufliciently powerful light source cannot be enclosed in a very small space because of the very considerable heat radiation which would not only spoil the microdocument in the vicinity thereof, but also the walls of the space allotted to the light source; any fan, being expensive, bulky and consuming power, is out of the question.

This invention remedies these various disadvantages. It relates to an apparatus for reading microdocuments comprising a case containing-an electric bulb, a source of power for the said bulb, an optical condenser, a filmholder designed to take the microdocument to be read,

a projection lens, at least one mirror to reflect the image and a screen cooperating in such a way that the condenser forms the image of the bulb filament in the lens'through the microdocument, and the lens forms an image of the microdocument on the screen after reflection from the mirror, the said mirror and the screen both being articulated and capable of being folded on to the case for transporting the apparatus, characterized by the use of a miniature bulb in combination with spherical units polished inside, centred on the bulb filament, and with an opening delimiting the light beam used by the condenser;

A better understanding of the invention will be gained from the following specification and the attached drawings.

FIG. 1 shows a diagrammatic section of the reader set up ready for use.

FIG. 2 shows the same apparatus folded, seen from the side.

FIGS. 3a and 3b show plane and profile views of a recovery ring in the bulb-holder.

FIGS. 4a and 4b show a variation of the recovery de' vice.

FIG. 1 shows, at l, a case ABCD, preferably made 'of plastics, used as a base for the apparatus; at 2, a very small-size bulb, preferably made of quartz, positioned under a sperical mirror centred on the filament, and surrounded by an annular device 4 for recovering the radiation from the bulb filament, which will be described further on; at 5, a condenser; at 6, a first'slanting mirror; at '0, a projection lens whose optical axis 8 reflects at Sr on to a second mirror 9 EF held by a holder 10 articulated on the case at 11; at GH, the translucent screen perpendicular to the optical axis 8r, mounted in a frame articulated on the case at 12. Finally, it shows, at 13, a slot in the case for inserting the. microdocument, which is pressed on to the output side of the condenser by a pressing device, not shown.

In addition, the reading apparatus comprises a device for moving the microdocument (at x and'at y, in the case of a microfiche in lines and columns), a device for focusing the lens, a compartment containing the dry cells and a switch for the electric circuit feeding the bulb; these are not shown, as they are of known type and their fitting is the responsability of the engineer; and fixing components, at predetermined angles, for the mirror-holder l0 and the screen-holder GH. FIG. 1 shows that the projecting beam is limited by GE, OF,

then by EH, FG. In addition, the apparatus includes a set of three light-weight walls, preferably made of plastics, and removable, protecting the whole of the light beam from surrounding light and enclosing it on top and on the sides. The centre wall I] is shown in dots and dashes; vertical dots and dashes from I and J show the start of the removable side protectors.

These three walls fold back on to one another and are housed in the case, preferably surrounding the frame of the screen in order to protect it. As a variation, and in order to provide better support for the three removable walls, the wall 10 is extended from E to Ea to form, with H, a substantially horizontal supporting plane; stops at H and Ea on the wall I] keep the apparatus rigid in the open position for projection. The side walls preferably reach down to the level of the case, and can be folded away across the width of the said case.

FIG. 2 Shows, folded back, the walls supporting the mirror EF, and the screen GH; the removable ll enclosing GI-I are not shown.

FIG. 3a gives a horizontally projecting view, and FIG. 3b gives a profile view as in FIG. 1, of the bulb-holder 14 with its recovery device consisting of two spherical units 15 and .16 focusing onthe same ideal sphere by means of two circular openings KL opposite each other in the flexible 'side walls of the U, and by means of two supports 17 resting on pins e in the U-shaped support. The units 15 and 16 are preferably made of pressed aluminium and polished inside. An opening 18 is provided in the top part of the top spherical unit, the said opening defining the effective field of light which has to be in the optical condenser, a bulb 19 having its filament 20 centred during construction in the centre of the protecting sphere; the socket of the said bulb is not shown. The bottomportion of the sphere has another circular opening which centres around a spherical mirror 21 provided during construction plumb with the filament 20;

FIGS. 4a and 4b show a variation of the spherical units in which the supports 17 are in a vertical plane instead of a horizontal plane.

In both cases, the recovery device works as follows.

The power radiated by the filament is very largely reflected back to it and recovered, except in the effective beam which goes through the condenser and forms the image of the microdocument on the screen. The filament gets its normal working temperature at a voltage far lower than that provided for a naked bulb. In this way, there is a saving of some of the cells, and the wear on them is decreased. Moreover, the recovery device serves as a screen and prevents dangerous heating of the parts of the apparatus which are in the vicinity of the bulb.

The components 17 also serve as cooling-fins to dissipate the heat frorn the conductor parts 15 and 16.

The foregoing specification is no way limits the scope of the invention, as the fixing of the spherical units can, inter alia, be different; the bottom opening can be eliminated to replace the mirror 21.

Similarly, the filament 20, instead of being plumb with the condenser, can be away from the microdocument area and radiate its light flux in a horizontal direction, reflected vertically by means of an auxiliary mirror.

What I claim is:

l. A portable apparatus for projecting and reading microdocuments comprising a case containing an electric bulb with a centered rear mirror, a source of power to said bulb, an optical condenser, a film holder designed to take and to position the microdocument to be projected, a projection lens, the condenser forming an image of the bulb filament in the lens through a selected part of the microdocument, the lens forming a virtual image of the selected part of said microdocument, at least one mirror reflecting said virtual image on a screen, said mirror and said screen both being articulated and adapted to be folded back on to the case for transporting the apparatus, wherein the case is substantially flat, said bulb extending into and surrounded by partial spherical units having inner polished surfaces centered on the bulb filament, said units being supported by a U-shaped member comprising two flexible parallel plane walls with two apertures centering and holding said units, said U-shaped member being fixed in the case of the apparatus at a predetermined place and having said rear mirror mounted thereon thus ensuring the correct positioning of the bulb filament on the axis of the optical system, said units further having a pair of opposed apertures along the optical axis, one delimiting the light beam used through the condenser and the other centered on said rear mirror, said polished surfaces adapted to reflect on the filament that part of the radiant energy which is not contained in the light beam passing through the condenser.

2. An apparatus in accordance with claim 1, wherein the units are equipted with cooling fins which diffuse the heat from said units. 

1. A portable apparatus for projecting and reading microdocuments comprising a case containing an electric bulb with a centered rear mirror, a source of power to said bulb, an optical condenser, a film holder designed to take and to position the microdocument to be projected, a projection lens, the condenser forming an image of the bulb filament in the lens through a selected part of the microdocument, the lens forming a virtual image of the selected part of said microdocument, at least one mirror reflecting said virtual image on a screen, said mirror and said screen both being articulated and adapted to be folded back on to the case for transporting the apparatus, wherein the case is substantially flat, said bulb extending into and surrounded by partial spherical units having inner polished surfaces centered on the bulb filament, said units being supported by a U-shaped member comprising two flexible parallel plane walls with two apertures centering and holding said units, said U-shaped member being fixed in the case of the apparatus at a predetermined place and having said rear mirror mounted thereon thus ensuring the correct positioning of the bulb filament on the axis of the optical system, said units further having a pair of opposed apertures along the optical axis, one delimiting the light beam used through the condenser and the other centered on said rear mirror, said polished surfaces adapted to reflect on the filament that part of the radiant energy which is not contained in the light beam passing through the condenser.
 2. An apparatus in accordance with claim 1, wherein the units are equipted with cooling fins which diffuse the heat from said units. 